So you want to measure alternating current, right? There are two ways. One is to use a shunt resistor, and the other is to use a transformer.
First approach has advantage of being simple and cheap, but also contributes power loss in circuit. Resistor can be really small (like 0.2R or something). Then you amplify and measure the voltage drop across shunt resistor.
Transformer approach uses a small tranfnormer with appropriate winding ratio where load current flows through primary and voltage is measured in secondary winding. This involves (probably) winding a custom impulse transformer, which is pain in the ass.